I got the batteries today. The box was a lot lighter than I had expected.
Opening it up was this:
And inside the pink bags were these. Their part number is SMPC 9 or SMPC9. Rated at 11.1V, 2.55Ah and 28.305Wh.
They were a lot smaller than I expected... Seems to be a theme I guess.
I'll have to look more into the BMS and connector stuff. I think I will probably end up breaking them up to make what I want, but its worth looking into.